In recent years it has become desirous to develop apparatus whereby the presence of a moving object within a static field may be accurately and quickly ascertained. More particularly, with the advent of the space age, it has become desirous that surveillance apparatus be presented whereby a static stellar field may be scanned for the determination of the presence of satellites.
To satisfy these desires, the prior art has taught the utilization of a standard vidicon for scanning the static field. Video signals from the vidicon are then stored within an electronic storage tube for purposes of maintaining a record of the field characteristics at a first point in time. At some later time, further video signals are taken from the vidicon relative to the particular field. These signals are inverted and stored in the electronic storage tube as a record of the characteristics of the field at the later point in time. The resulting difference image can be read out of the electronic storage tube which clearly relates the presence or absence of moving objects within the field. This prior art technique requires complex circuitry to achieve the desired determination and more particularly requires the presence of an input vidicon and inverting circuitry in conjunction with a standard electronic storage tube.
It has been known in the prior art that an optical image correlator tube may be utilized for purposes of storing on a storage mesh thereof data indicative of the relative brightness levels of objects within a field. It has further been known that an image dissector tube may be utilized for purposes of scanning a field as the same is sensed by the photocathode thereof.
To date, there has not been presented any devices incorporating, in a single unit, the storage capabilities of an optical image correlator and the image dissecting capabilities of an image dissector tube wherein the storage mesh may be operated in each of two distinct storage modes with the stored data thereof being dissected and the resultant outputs being analyzed by associated circuitry for the determination of the presence of moving objects and the positions thereof within the field.
It is consequently an object of the instant invention to present a storage tube moving target detector incorporating in a single device the capabilities of both storing and dissecting the stored difference.
A further object of the invention is to present a storage tube moving target detector wherein the storage mesh thereof may be written on in either of two distinct modes by altering the biasing thereof with respect to a photocathode.
Yet another object of the invention is to present a storage tube moving target detector utilizing output circuitry whereby the determination of the presence and position of a moving object within a field may be made.
Still a further object of the invention is to present a storage tube moving target detector which is relatively simplistic in design, inexpensive to construct, highly reliable and accurate in operation, and an advancement over the prior art of such apparatus.
These objects and other objects which will become apparent as the detailed description proceeds are achieved by apparatus for determining the presence and position of a moving object within a field, comprising first means for emitting electrons as a function of the amplitude of light from the field incident thereto; second means for receiving said electrons and storing a distributive charge thereon indicative of time related displacements of moving light levels within the field; and third means for controllably scanning said second means and operative to create output signals as a function of the charge distribution on said second means.